Sonarr not grabbing nzbs even when it's available with indexer

[Jason_Ang]

Sonarr version (exact version): 2.0.0.3732
Mono version (if Sonarr is not running on Windows): 4.2.2 (Stable 4.2.2.30/996df3c Sun Jan 31 11:58:08 UTC 2016)
OS: Unraid
Debug logs (posted to hastebin or similar):

Sonarr is not grabbing shows even when nzb already available in indexer. Seeing this, I manually selected the episode, and do a manual search, it gives me results from the indexer. But upon downloading the nzb, it turns into a red cloud symbol, and says “failed…” I will attach screenshot here.

[markus101]

Its failing, either downloading the NZB from the indexer or when it tries to send it to the download client, debug logs will tell you why.